am f3a142b8: am 7eaa4dc2: Merge "Link against Mac OSX 10.5 SDK if building on 10.6." into gingerbread

Merge commit 'f3a142b8d5b4db7299b706653f4fd2952f4e5d8c'

* commit 'f3a142b8d5b4db7299b706653f4fd2952f4e5d8c':
  Link against Mac OSX 10.5 SDK if building on 10.6.